The Energy Balance and Body Composition Core (Core D) serves investigators across the institution to quantify energy balance and body composition in mice. Accurate quantification of these parameters is essential for studies focused on obesity, with wide-spread capabilities for metabolism-related studies. The core houses 24 LabMaster TSE chambers that quantify food and water intake, physical activity and indirect calorimetry in mice, a common model for studies focused on the effect of diet or genetics on the development of obesity. The Core also houses an EchoMRI to quantify lean and fat mass and total body water in conscious mice. Both systems allow for non-invasive longitudinal assessment of energy balance and body composition. Competent core staff maintain and oversee the use of the LabMaster TSE system and train personnel in use of the EchoMRI. Core Directors assist in study design and data handling and analysis. Over 50 Principal Investigators use the LabMaster TSE system annually for studies on >700 mice/year, while the EchoMRI is used by more than 25 laboratories annually. These systems are not duplicated at the institution or within the Commonwealth, and are vital to our ability to reduce the epidemic of obesity in Kentucky. In Phase III of the program, we will broaden our focus to include obesity as a risk factor for cardiovascular diseases, diabetes, cancer and neurodegenerative diseases. This will increase use of the system to support an anticipated larger user base with targeted growth within these areas across the institution. We will also purchase a new system, from institutional support, that will markedly expand capabilities of this core in quantifying energy metabolism in mice. Also, during Phase III of the program the core for this system, including all equipment, will be relocated to a modern animal care facility within a new research building that is dedicated to the study of these health disparities. We anticipate that this core will transition to self-sustaining capacity over the course of Phase III support of the COCVD.